Thalassemia is an inherited blood disorder that affects the body's ability to produce hemoglobin and red blood cells.
A person with thalassemia will have too few red blood cells and too little hemoglobin, and the red blood cells may be too small.
The impact can range from mild to severe and life-threatening.
Around 100,000 newborns are delivered each year with severe forms of thalassemia. It is most common with Mediterranean, South Asian, and African ancestry.
The symptoms of thalassemia vary depending on the type of thalassemia.
Symptoms will not show until the age of 6 months in most infants with beta thalassemia and some types of alpha thalassemia. This is because neonates have a different type of hemoglobin, called fetal hemoglobin.
After 6 months "normal" hemoglobin starts replacing the fetal type, and symptoms may begin to appear.
- jaundice and pale skin
- drowsiness and fatigue
- chest pain
- cold hands and feet
- shortness of breath
- leg cramps
- rapid heart beat
- poor feeding
- delayed growth
- dizziness and faintness
- greater susceptibility to infections
Skeletal deformities may result as the body tries to produce more bone marrow.
If there is too much iron, the body will try to absorb more iron to compensate. Iron may also accumulate from blood transfusions. Excessive iron can harm the spleen, heart, and liver.
Patients with hemoglobin H are more likely to develop gallstones and an enlarged spleen.
Untreated, the complications of thalassemia can lead to organ failure.
Treatment depends on the type and severity of thalassemia.
Blood transfusions: These can replenish hemoglobin and red blood cell levels. Patients with thalassemia major will need between eight and twelve transfusions a year. Those with less severe thalassemia will need up to eight transfusions each year, or more in times of stress, illness, or infection.
Iron chelation: This involves removing excess iron from the bloodstream. Sometimes blood transfusions can cause iron overload. This can damage the heart and other organs. Patients may be prescribed deferoxamine, a medication that is injected under the skin, or deferasirox, taken by mouth.
Patients who receive blood transfusions and chelation may also need folic acid supplements. These help the red blood cells develop.
Bone marrow, or stem cell, transplant: Bone marrow cells produce red and white blood cells, hemoglobin, and platelets. A transplant from a compatible donor may be an effective treatment, in severe cases.
Surgery: This may be necessary to correct bone abnormalities.
Gene therapy: Scientists are investigating genetic techniques to treat thalassemia. Possibilities include inserting a normal beta-globin gene into the patient's bone marrow, or using drugs to reactivate the genes that produce fetal hemoglobin.
The protein hemoglobin transports oxygen around the body in blood cells. Bone marrow uses the iron we get from food to make hemoglobin.
In people with thalassemia, the bone marrow does not produce enough healthy hemoglobin or red blood cells. In some types this leads to a lack of oxygen, resulting in anemia and fatigue.
People with mild thalassemia may not require any treatment, but more severe forms will necessitate regular blood transfusions.
Most children with moderate to severe thalassemia receive a diagnosis by the time they are 2 years old.
People with no symptoms may not realize that they are carriers until they have a child with thalassemia.
Blood tests can detect if a person is a carrier or if they have thalassemia.
A complete blood count (CBC): This can check levels of hemoglobin and the level and size of red blood cells.
A reticulocyte count: This measures how fast red blood cells, or reticulocytes, are produced and released by the bone marrow. Reticulocytes usually spend around 2 days in the bloodstream before developing into mature red blood cells. Between 1 and 2 percent of a healthy person's red blood cells are reticulocytes.
Iron: This will help the doctor determine the cause of anemia, whether thalassemia or iron deficiency. In thalassemia, iron deficiency is not the cause.
Genetic testing: DNA analysis will show whether a person has thalassemia or faulty genes.
Prenatal testing: This can show whether a fetus has thalassemia, and how severe it might be.
- Chorionic villus sampling (CVS): a piece of placenta is removed for testing, usually around the 11th week of pregnancy.
- Amniocentesis: a small sample of amniotic fluid is taken for testing, usually during the 16th week of pregnancy. Amniotic fluid is the fluid that surrounds the fetus.
Four alpha-globin and two beta-globin protein chains make up hemoglobin. The two main types of thalassemia are alpha and beta.
In alpha thalassemia, the hemoglobin does not produce enough alpha protein.
To make alpha-globin protein chains we need four genes, two on each chromosome 16. We get two from each parent. If one or more of these genes is missing, alpha thalassemia will result.
The severity of thalassemia depends on how many genes are faulty, or mutated.
One faulty gene: The patient has no symptoms. A healthy person who has a child with symptoms of thalassemia is a carrier. This type is known as alpha thalassemia minima.
Two faulty genes: The patient has mild anemia. It is known as alpha thalassemia minor.
Three faulty genes: The patient has hemoglobin H disease, a type of chronic anemia. They will need regular blood transfusions throughout their life.
Four faulty genes: Alpha thalassemia major is the most severe form of alpha thalassemia. It is known to cause hydrops fetalis, a serious condition in which fluid accumulates in parts of the fetus' body.
A fetus with four mutated genes cannot produce normal hemoglobin and is unlikely to survive, even with blood transfusions.
Alpha thalassemia is common in southern China, Southeast Asia, India, the Middle East, and Africa.
We need two globin genes to make beta-globin chains, one from each parent. If one or both genes are faulty, beta thalassemia will occur.
Severity depends on how many genes are mutated.
One faulty gene: This is called beta thalassemia minor.
Two faulty genes: There may be moderate or severe symptoms. This is known as thalassemia major. It used to be called Colley's anemia.
Beta thalassemia is more common among people of Mediterranean ancestry. Prevalence is higher in North Africa, West Asia, and the Maldive Islands.
Various complications can arise.
This may be due to the frequent blood transfusions or the disease itself.
The endocrine glands produce hormones. The pituitary gland is particularly sensitive to iron overload. Damage may lead to delayed puberty and restricted growth. Later, there may be a higher risk of developing diabetes and either an underactive or overactive thyroid gland.
Sometimes, a blood transfusion will trigger a reaction where the person's immune system reacts to the new blood and tries to destroy it. It is important to have the exact blood type match to prevent this kind of problem.
The spleen recycles red blood cells. In thalassemia, the red blood cells may have an abnormal shape, making it harder for the spleen to recycle them. The cells accumulate in the spleen, making it grow.
An enlarged spleen can become overactive. It can start to destroy the healthy blood cells the patient receives during transfusions. Sometimes, a patient may need a splenectomy, or surgical removal of the spleen. This is now less common, because removing the spleen can lead to other complications.
Removing the spleen leads to a higher chance of infection, and regular transfusions increase the risk of contracting a blood-borne disease.
In some cases, the bone marrow expands, deforming the bone around it, especially the bones of the skull and face. The bone can become brittle, increasing the risk of fracture.
Living with thalassemia
Depending on the type of thalassemia, constant medical care may be necessary to manage the condition effectively. Those receiving transfusions must be sure to follow their transfusion and chelation schedule.
People with thalassemia are advised to:
- attend all their regular appointments
- maintain contact with friends and support networks, to help keep a positive attitude
- follow a healthy diet to maintain good health
- get a suitable amount of exercise
Some foods, such as spinach or iron-enriched cereals, may have to be avoided, to prevent excessive iron buildup. Patients should discuss dietary and exercise options with their doctor.
The Centers for Disease Control and Prevention (CDC) urge people with thalassemia to keep their vaccinations up to date, to prevent illness.
This is especially important for those who receive transfusions, as they have a higher risk of contracting hepatitis A or B.
Thalassemia and pregnancy
Anyone considering pregnancy should first seek genetic counseling, especially if both partners have or may have thalassemia.
During pregnancy, a woman with thalassemia may have a higher risk of cardiomyopathy and diabetes. There may be fetal growth restriction, too.
The mother should be assessed by a cardiologist or hematologist before and during pregnancy, to minimize problems, especially if she has thalassemia beta minor.
During delivery, continuous fetal monitoring may be recommended.
The outlook depends on the type of thalassemia.
A person with the thalassemia trait has a normal life expectancy. However, heart complications arising from beta thalassemia major can make this condition fatal before the age of 30 years.